D. Malamis

Overview of water usage and wastewater management in the food and beverage industry

AbstractFood and beverage industry is one of the major contributors to the growth of all economies. In European Union, it constitutes the largest manufacturing sector in terms of turnover, value added, and employment. However, the sector has been associated with various environmental issues including high levels of water consumption and wastewater production. In the present work, an overview regarding the production process, the water usage and the wastewater generation, and treatment of representative manufacturing industries from selected sectors of the food and beverage industry, is presented. The industries under investigation are: slaughterhouses, potato processing, olive oil production, cheese production, and beer manufacturing. As expected, between those different sectors, water consumption and wastewater generation vary greatly. Wastewater pollution load depends on the type of product being processed, the process and the equipment used, while the common characteristic is the strong organic content...

An overview on desalination & sustainability: renewable energy-driven desalination and brine management

AbstractDesalination is a water technology that is gaining increasing importance for addressing water needs, but it is costly and energy intensive and further strains the environment with brine disposal and greenhouse gas (GHG) emissions. In order to desalt seawater, either through membrane or thermal processes, a large amount of energy is required. Desalination has negative impacts in the form of depletion of fossil fuels and GHG emissions from the power production process to deliver this energy. What is more, the wastewater (brine) produced during the desalination process causes damages to the local sea environment where the brine is discharged. In order for desalination to be considered a sustainable water solution, both issues must be successfully resolved. This paper discusses the potential for coupling desalination with renewable energy (RES-D). Different renewable technologies can be combined with certain desalination techniques. The technical development stage of the RES-D combinations already app...

Thermochemical valorization and characterization of household biowaste

Valorization of municipal solid waste (MSW), by means of energy and material recovery, is considered to be a crucial step for sustainable waste management. A significant fraction of MSW is comprised from food waste, the treatment of which is still a challenge. Therefore, the conventional disposal of food waste in landfills is being gradually replaced by recycling aerobic treatment, anaerobic digestion and waste-to-energy. In principle, thermal processes like combustion and gasification are preferred for the recovery of energy due to the higher electrical efficiency and the significantly less time required for the process to be completed when compared to biological process, i.e. composting, anaerobic digestion and transesterification. Nonetheless, the high water content and the molecular structure of biowaste are constraining factors in regard to the application of thermal conversion pathways. Investigating alternative solutions for the pre-treatment and more energy efficient handling of this waste fraction may provide pathways for the optimization of the whole process. In this study, by means of utilizing drying/milling as an intermediate step, thermal treatment of household biowaste has become possible. Household biowaste has been thermally processed in a bench scale reactor by means of torrefaction, carbonization and high temperature pyrolysis. According to the operational conditions, fluctuating fractions of biochar, bio-oil (tar) and syngas were recovered. The thermochemical properties of the feedstock and products were analyzed by means of Simultaneous Thermal Analysis (STA), Ultimate and Proximate analysis and Attenuated Total Reflectance (ATR). The analysis of the products shows that torrefaction of dried household biowaste produces an energy dense fuel and high temperature pyrolysis produces a graphite-like material with relatively high yield.

The existing situation and challenges regarding the use of plastic carrier bags in Europe

Since day one, retailers and consumers have favoured plastic carrier bags. However, owing to the numerous environmental disadvantages, lightweight plastic carrier bags have been drawing the attention of the European Union competent authorities. Therefore, many European Union member states have taken action so as to reduce the use of plastic carrier bags. Based on the existing legislation and voluntary initiatives for the reduction of lightweight plastic carrier bags, the challenges and achieved outcomes from the implemented policy options in the various European Union member states are discussed and commented regarding the forthcoming transposition of the ‘Directive 94/62/EC on packaging and packaging waste to reduce the consumption of lightweight plastic carrier bags’ into the European Union member states’ national law.

Utilisation of biomass gasification by-products for onsite energy production.

Small scale biomass gasification is a sector with growth and increasing applications owing to the environmental goals of the European Union and the incentivised policies of most European countries. This study addresses two aspects, which are at the centre of attention concerning the operation and development of small scale gasifiers; reuse of waste and increase of energy efficiency. Several authors have denoted that the low electrical efficiency of these systems is the main barrier for further commercial development. In addition, gasification has several by-products that have no further use and are discarded as waste. In the framework of this manuscript, a secondary reactor is introduced and modelled. The main operating principle is the utilisation of char and flue gases for further energy production. These by-products are reformed into secondary producer gas by means of a secondary reactor. In addition, a set of heat exchangers capture the waste heat and optimise the process. This case study is modelled in a MATLAB-Cantera environment. The model is non-stoichiometric and applies the Gibbs minimisation principle. The simulations show that some of the thermal energy is depleted during the process owing to the preheating of flue gases. Nonetheless, the addition of a secondary reactor results in an increase of the electrical power production efficiency and the combined heat and power (CHP) efficiency.

Research on the drying kinetics of household food waste for the development and optimization of domestic waste drying technique

ABSTRACT Domestic food waste drying foresees the significant reduction of household food waste mass through the hygienic removal of its moisture content at source. In this manuscript, a new approach for the development and optimization of an innovative household waste dryer for the effective dehydration of food waste at source is presented. Food waste samples were dehydrated with the use of the heated air-drying technique under different air-drying conditions, namely air temperature and air velocity, in order to investigate their drying kinetics. Different thin-layer drying models have been applied, in which the drying constant is a function of the process variables. The Midilli model demonstrated the best performance in fitting the experimental data in all tested samples, whereas it was found that food waste drying is greatly affected by temperature and to a smaller scale by air velocity. Due to the increased moisture content of food waste, an appropriate configuration of the drying process variables can lead to a total reduction of its mass by 87% w/w, thus achieving a sustainable residence time and energy consumption level. Thus, the development of a domestic waste dryer can be proved to be economically and environmentally viable in the future.

Adaptation measures for the food and beverage industry to the impact of climate change on water availability

AbstractWater is used as an ingredient, as an essential processing element, as a cooling agent and for the cleaning of equipment and installations in many food and beverage industries. Consequently, the sector is affected by the impact of climate change of reduced water availability. This paper presents current issues related to water demand in the food and beverage industry and addresses adaptation measures in response to reduced water availability. The food and drink industry is a large drinking quality water consumer. Owing to that, the sector has to adopt reduction and minimisation measures in line with the Best Available Techniques. In particular, some general measures can be adopted by all industries of the sector, while other measures are sector-specific measures including the meat and poultry processing sector, the fish processing sector, the fruit and vegetables division, dairies and the drink manufacturing industry. Through widespread adoption of water reducing and minimisation measures, the sec...

Development of a decentralized innovative brackish water treatment unit for the production of drinking water

Access to water constitutes a necessary condition in order to ensure life. This paper deals with the development of an innovative energy autonomous system in order to provide drinking water in isolated small communities, using brackish water as feedstock. The case study is a small village in Jordan, where the system that was designed and constructed in Greece, was installed. The unique characteristic of the innovative system is its compact form that incorporates the reverse osmosis unit and the renewable energy production from three sources, wind, solar and water. The energy autonomous system for the production of drinking water from brackish water can be used as a decentralized unit for isolated areas where access to clean water and electricity is not available.

Sustainable management of brine effluent from desalination plants: the SOL-BRINE system

AbstractDesalination comprises a non-conventional water resource practice that is currently gaining importance internationally for filling the gap in the water balance. Even though it is a well proven technique, it is associated with certain economic considerations (high energy consumption) and environmental concerns regarding brine management: around 2 L of wastewater are generated for every liter of freshwater produced. The high concentration of salts in this wastewater can create serious disposal problems. The SOL-BRINE project sought to eliminate water pollution and environmental damage associated with brine release, by introducing a new technique capable of achieving zero liquid discharge from desalination plants. The demonstration plant that is presented in this paper was installed at Agios Fokas area, Tinos Island in Greece in October 2012 and has been operated regularly since January 2013. The plant has the capacity to treat over 200 tons of brine per year.

Improvement of home composting process of food waste using different minerals

This article presents the experimental study of the process of composting in a prototype home-scale system with a special focus on process improvement by using different additives (i.e. woodchips, perlite, vermiculite and zeolite). The interventions with different bulking agents were realized through composting cycles using substrates with 10% additives in specific mixtures of kitchen waste materials. The pre-selected proportion of the mixtures examined was 3:1:1 in cellulosic:proteins:carbohydrates, in order to achieve an initial C/N ratio equal to 30. The control of the initial properties of the examined substrates aimed at the consequent improvement of the properties of the final product (compost). The results indicated that composting process was enhanced with the use of additives and especially the case of zeolite and perlite provided the best results, in terms of efficient temperature evolution (>55 °C for 4 consecutive days). Carbon to nitrogen ratios decreased by 40% from the initial values for the reactors were minerals were added, while for the bioreactor tested with woodchips the reduction was slight, showing slowest degradation rate. Moisture content of produced compost varied within the range of 55-64% d.m., while nutrient content (K, Na, Ca, Mg) was in accordance with the limit values reported in literature. Finally, the composts obtained, exhibited a satisfactory degree of maturity, fulfilling the criterion related to the absence of phytotoxic compounds.